Smokeless tobacco (SLT) use has important health consequences, including nicotine dependence, cancer, and periodontal disease, among others. Young adults aged 18-25, including both those in college and those who are not, have the highest prevalence of use of any adult age group. SLT companies intentionally market SLT products to college students. New products, including snus and alternative products (lozenges, dissolvable strips, orbs, and sticks), are being marketed as ways for smokers to get nicotine in places where smoking is not permitted-a condition that is increasingly the norm on college campuses. The goal of this study is to better understand trajectories and correlates of SLT use among college students. Specific Aim 1: To measure trajectories of SLT use among undergraduate college students over the course of their college careers. To accomplish this aim, we will recruit a cohort of SLT users and non-users from 10 colleges in North Carolina and will follow this cohort using web-based surveys beginning in their freshman year and continuing throughout their college careers. Specific Aim 2: To identify environmental and individual-level correlates of trajectories of SLT use. To assess individual-level correlates, we will use data from the longitudinal web surveys of our cohort, which will assess many possible correlates of SLT use. To assess environmental-level correlates, we will conduct an annual environmental assessment of each college campus and surrounding community to measure campus and community policies related to SLT use, point-of-purchase advertising and sales, and promotional events in local bars. Specific Aim 3: To examine patterns of use of different SLT products, including chewing tobacco, dry and moist snuff (including snus and other flavored products), and alternative products (including lozenges, strips, orbs, and sticks). To accomplish this aim, we will use data from the longitudinal web-based student surveys, which will measure use and knowledge of multiple SLT products. Results from this study will contribute to understanding factors associated with SLT initiation, progression and cessation and will provide the basis for developing effective interventions and policy.